Hydrodesulfurization of oil utilizing a catalyst of rare earth metal, non-rare earth metal and alumina support

ABSTRACT

A catalyst is provided which comprises a hydrogenation component composited with a support. The hydrogenation component comprises a rare earth metal component and a transition metal component. Preferred catalysts are bimetallic catalysts consisting of cobalt and a rare earth metal on an alumina support. Also provided is a hydrodesulfurization process utilizing said catalyst.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a catalyst and process forhydrodesulfurization of mineral oils. More particularly, this inventionrelates to a catalyst comprising a rare earth metal component and atransition metal component composited with a support.

2. Description of the Prior Art

Hydrodesulfurization processes in which heavy hydrocarbon distillates orresidual fractions are hydrotreated with hydrogen in the presence of acatalyst comprising a hydrogenation component composited with arefractory oxide support, such as alumina, are well known (see forexample U.S. Pat. Nos. 3,531,399; 3,569,044 and 3,770,618).

Catalysts comprising a rare earth metal component are also known.

It has now been found that a hydrodesulfurization catalyst comprising arare earth metal component and a transition metal component compositedwith a support provides advantages that will become apparent in thefollowing description.

SUMMARY OF THE INVENTION

In accordance with the invention there is provided, a process for thehydrodesulfurization of a sulfur-containing hydrocarbon oil whichcomprises contacting said oil under hydrodesulfurization conditions withhydrogen and a catalyst comprising a hydrogenation component and asupport, said hydrogenation component comprising from about 1 to about15 weight percent of a first metal component and from about 1 to about 5weight percent of the second metal component, said first metal componentbeing a rare earth metal component wherein the rare earth metalconstituent of said component is selected from the group consisting ofelements having atomic numbers ranging from 58 to 71 and wherein themetal constituent of the said second metal component is a non-rare earthmetal selected from the group consisting of Groups IB, IIB, IIIB, IVB,VIB and VIIIB of the Periodic Table of Elements.

Furthermore, in accordance with the invention there is provided acatalyst comprising a hydrogenation component and a support, saidhydrogenation component comprising from about 1 to about 15 weightpercent of a first metal component and from about 1 to about 5 weightpercent of a second metal component, said first metal component being arare earth metal component wherein the rare earth metal constituent ofsaid component is selected from the group consisting of elements havingatomic numbers ranging from 58 to 71 and wherein the metal constituentof said second metal component is a non-rare earth metal selected fromthe group consisting of Group IB, Group IIB, Group IIIB, Group IVB,Group VIB and Group VIIIB of the Periodic Table of Elements.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A sulfur-containing heavy hydrocarbon feedstock is contacted in ahydrodesulfurization zone with hydrogen and a catalyst of the presentinvention under hydrodesulfurization conditions to produce a hydrocarbonproduct having a reduced content of sulfur.

HEAVY HYDROCARBON FEEDSTOCKS

The heavy hydrocarbon feedstocks utilized in the present inventioncomprise hydrocarbons boiling above 650° F. (343.33° C) at atmosphericpressure which contain substantial quantities of material boiling above1,000° F. (537.78° C). The process is particularly suited for treatingheavy crude mineral oils, residual petroleum oil fractions, such asfractions produced by atmospheric and vacuum distillation of crude oils.Such residual oils usually contain large amounts of sulfur and metalliccontaminants such as nickel and vanadium. The total metal content ofsuch oils may range up to 2,000 weight parts per million or more and thesulfur content may range up to 8 weight percent or more. The Conradsoncarbon residue of these heavy hydrocarbon feeds will generally rangefrom about 5 to about 50 weight percent (as to Conradson carbon residue,see ASTM test D-189-65). The preferred process feedstock is a petroleumresiduum obtained from distillation or other treating or separationprocess. From about 30 to about 100 percent of the petroleum residuumfeed boils above 900° F. (482.22° C.) at atmospheric pressure. Othersuitable feedstocks include heavy hydrocarbons recovered from tar sands;synthetic crude oils recovered from oil shales; heavy oils produced fromthe liquefaction of coal and the like, and mixtures of any of thesefeeds. The hydrocarbon feeds will generally contain at least 10 percentof materials boiling above 1,000° F. (537.78° C.) at atmosphericpressure.

OPERATING CONDITIONS IN THE HYDRODESULFURIZATION ZONE

The operating conditions in the hydrodesulfurization zone include atemperature ranging from about 100° C. (212° F.) to about 700° C.(1,382° F.), preferably a temperature ranging from about 300° C. (572°F.) to about 500° C. (932° F.), a hydrogen partial pressure ranging fromabout 1 atmosphere to about 10,000 psig, preferably from about 30 psigto about 1,000 psig, for example, about 175 psig; a liquid hourly spacevelocity ranging from about 0.5 volumes of hydrocarbon feed per hour pervolume of catalyst to about 30 volumes of hydrocarbon feed per catalyst(V/V/Hr.), preferably from about 1.0 V/V/Hr. to about 5.0 V/V/Hr., and ahydrogen rate of about 2 to about 200 standard cubic feet per barrel ofhydrocarbon feed.

THE HYDRODESULFURIZATION CATALYST

The hydrodesulfurization catalyst of the present invention utilized inthe hydrodesulfurization zone comprises a hydrogenation componentcomprising a first metal component and a second metal component. Thefirst metal component is a rare earth metal component selected from thegroup of elements having atomic numbers ranging from 58 to 71. Thesecond metal component is a non-rare earth transition metal component.The metallic components are composited with a support.

Suitable rare earth metal components include the elemental rare earthmetals or compounds, such as oxides, or sulfides of cerium,praseodymium, neodymium, promethium, samarium, europium, gadolinium,terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium andmixtures thereof. Preferably, the rare earth metal constituent of thecomponent is selected from the group having atomic numbers ranging from59 to 71 and mixtures thereof. More preferably, the rare earth metalconstituent of the component is selected from the group consisting ofPr, Nd, Sm, Eu, Gd, Dy, Er, Yb and mixtures thereof.

The rare earth metal component is present in the catalyst in an amountranging from about 1 to about 15 weight percent, preferably from about 5to about 15 weight percent, calculated as the elemental metal, based onthe total catalyst.

The second metal component of the catalyst is an elemental metal or acompound such as an oxide or a sulfide of a non-rare earth transitionmetal selected from the group consisting of Groups IB, IIB, IIIB, IVB,VIB and VIIIB of the Periodic Table of Elements. The Periodic Tablereferred to herein is in accordance with the Handbook of Chemistry andPhysics published by the Chemical Rubber Publishing Company, Cleveland,Ohio, 45th Edition, 1964. Preferably the second metal component isselected from the group consisting of Group VIB and Group VIIIB. Morepreferably, the second metal component is a Group VIIIB metal, that is,iron, cobalt or nickel. The second metal component may suitably bepresent in a catalyst in an amount ranging from about 1 to about 5weight percent, preferably from about 1 to about 3 weight percent,calculated as the elemental metal, based on the total catalyst.

The preferred catalyst of the present invention is a bimetalliccatalyst, that is, the hydrogenation component of the catalyst consistsessentially of a rare earth metal component and the second metalcomponent which is selected from a group other than a rare earth metal.

The support for the hydrogenation component may be any of theconventional supports, such as refractory oxides, for example, alumina,silica, silica-alumina. A preferred support is an alumina-containingsupport. A more preferred support is an alumina prepared by the thermaldecomposition of aluminum alcoholates according to the method describedin the publication J. L. Gass and S. J. Teichner in Bull. Soc. Chim.,France, 1972 (6)2209-13, see also Ibid 1973 (2)429-35.

Generally, the method comprises a careful hydrolysis of an aluminumalcholate (for example, an aluminum butylate) to produce aluminumhydroxide followed by a thermal decomposition of the aluminum hydroxidein a solvent at a temperature above the critical temperature of thesolvent. Suitable solvents include alcohols, preferably the lowerboiling alcohols such as C₁ to C₄ alcohols, acetone, methylethyl ketone,cyclic ethers, tetrahydrofuran and the like. Suitable thermaldecomposition temperatures range from above the critical temperature ofthe particular solvent used to about 980° C., preferably from about 700°to about 980° C.

The catalyst of the present invention is suitably prepared byimpregnating the support with a solution of the salt of the firstdesired metal component, sintering the impregnated support, followed byimpregnation of the sintered material with a solution of a salt of thesecond desired metal component, followed by sintering of the impregnatedmaterial. Thus, a sequential impregnation with intervening sintering isa preferred manner of preparing the catalyst.

The following examples are presented to illustrate the invention.

EXAMPLE 1

Preparation of a cobalt-europium catalyst on eta-alumina (to bedesignated herein catalyst A) was carried out as follows: a commerciallyavailable eta-alumina (10 g; surface area about 110 m² /g) was placed ina closed vapor saturation chamber with excess water at ambienttemperature for 16 hours. Then a solution of 3.53 g of Eu(NO₃)₃.6H₂ Odissolved in 6.5 g of water was impregnated into the water vapor treatedsample of alumina. Following impregnation, the material was placed in aceramic boat in a quartz tube contained in a tube furnace. Here it washeated at 88° C. for 1 hour under a stream of pure oxygen flowing at 20ml/minutes. It was slowly heated over 2 hours to a temperature of 540°C. where it was held for 1 hour under the same oxygen flow. Aftercooling, the powder was again placed into the water vapor saturationchamber for 16 hours. Then 1.194 g of Co(NO₃)₂.6H₂ O and 6.5 g of waterwas used to impregnate the above sintered solid utilizing an identicalsintering procedure. The resultant surface area of this material was 85m² -g minus 1.

The following catalysts: Co-Pr, Co-Sm, Co-Nd, Co-Er, Co-Yb and Co-Dywere prepared in a similar manner and in similar concentrations. Thecatalysts were presulfided in a conventional manner prior to testing. Afeed consisting of 5 percent dibenzothiophene in a hydrocarbon mixturewas passed over the respective catalysts at 350° C., 175 psig hydrogenpressure, utilizing a liquid flow velocity of 3.3 V/V/Hr. and a hydrogenflow rate of 40 ml per minute. Another series of tests was made undersimilar conditions except for the temperature of the reaction zone was450° C.

Results of the tests are summarized in Table I. Each of the catalystsdesignated catalysts A, D, E, F, G, H, I and J comprised 2.35 weightpercent cobalt, calculated as the elemental metal based on the totalcatalyst, and 11.1 weight percent of the specified rare earth metal,calculated as the elemental metal based on the total catalyst.

                                      TABLE I                                     __________________________________________________________________________    COBALT - RARE EARTH METAL CATALYSIS OF DIBENZOTHIOPHENE DESULFURIZATION       175 psig hydrogen pressure, .sup.(a) 20 ml feed-hr.sup.-1, (b) 6.0 ml         catalyst presulfided with 15% H.sub.2 S in H.sub.2                            at 400° C. for 1 hour. All conversions are rates after 3.0 hr. on      feed.                                                                                                    Specific  Weight    Volume    Percent                           Surface Area                                                                          Density                                                                             Reactivity.sup.(e)                                                                      Reactivity.sup.(f)                                                                      Reactivity.sup.(g)                                                                      Feed                 Catalyst     (m.sup.2 /gm)                                                                         (gm/ml)                                                                             (mol-sec.sup.-1 -m.sup.-2)                                                              (mol-sec.sup.-1 -gm.sup.-1)                                                             (mol-sec.sup.-1 -ml.sup.-1)                                                   1         Cracking             __________________________________________________________________________    Reaction Temperature 350° C.                                           A. Co-Eu     85      0.47  16.2      13.7      6.4       0                    B. Conventional Cat..sup.(c)                                                               245     0.72  11.1      28.3      20.4      0                    C. Conventional Cat..sup.(d)                                                               245     --    5.2       13.2      9.5       0                    D. Co-Pr     76      0.54  5.4       4.1       2.2       0                    E. Co-Nd     83      0.51  9.3       7.7       3.9       0                    F. Co-Sm     81      0.52  9.5       7.7       4.0       0                    G. Co-Gd     77      0.44  6.28      4.9       2.2       0                    H. Co-Dy     --      0.44  --        0.23      0.1       0                    I. Co-Er     74      0.51  3.7       2.7       1.4       0                    J. Co-yb     73      0.47  4.4       3.2       1.5       0                    Reaction Temperature 450° C.                                           A. Co-Eu     85      0.47  23.0      19.5      9.2       0.0                  B. Conventional Cat..sup.(c)                                                               245     0.72  11.6      29.6      20.3      4.7                  C. Conventional Cat..sup.(d)                                                               245     --    9.6       24.6      17.6      --                   D. Co-Pr     76      0.54  23.8      18.1      9.8       1.9                  E. Co-Nd     83      0.51  12.9      10.7      5.5       0.5                  F. Co-Sm     81      0.52  17.3      13.9      7.2       0.0                  G. Co-Gd     77      0.44  21.9      16.9      7.4       0.2                  H. Co-Dy     --      0.44  --        10.4      4.6       0.7                  I. Co-Er     74      0.51  5.9       4.3       2.2       0.0                  J. Co-Yb     73      0.47  10.8      7.9       3.7       0.0                  __________________________________________________________________________     .sup.(a) Hydrogen flow rate was 40 ml/min.                                    .sup.(b) Feed contained 5 wt. % dibenzothiophene, 2% dibenzyl, 10%            diphenylmethane and 83% hexadecane.                                           .sup.(c) Results of best run.                                                 .sup.(d) Average value for 4 runs.                                            .sup.(e) Specific reactivity × 10.sup.-10                               .sup.(f) Weight reactivity × 10.sup.-8                                  .sup.(g) Volume reactivity × 10.sup.-8                             

As can be seen from the data in Table I, the catalysts of the presentinvention were more active than the conventional prior art catalysts.

EXAMPLE 2

Another series of tests was conducted at atmospheric hydrogen pressureutilizing space velocity of 3.3 V/V/Hr. at 350° and at 450° C.,respectively, with the same feed as the one utilized in Example 1, witha different set of catalysts.

Results of these tests are shown in Table II.

                  TABLE II                                                        ______________________________________                                        SPECIFIC REACTIVITY.sup.(a) OF TRANSITION                                     METAL-NEODYMIUM DESULFURIZATION                                                                              Percent                                                       Specific Reactivity.sup.(c)                                                                   Cracking                                       Catalyst.sup.(b)                                                                              (mol-sec.sup.-1 -in.sup.-2)                                                                  at 450° C.                              ______________________________________                                                       350° C.                                                                           450° C.                                      B. Conventional                                                                              2.6        0.29      9.1                                       K. Alumina Support                                                                           0          0         4.7                                       L. 10% Nd on Alumina                                                                         0.2        0.2       0.8                                       M. Co-Nd       1.1        0.5       0.0                                       N. Ni-Nd       4.6        1.3       0.6                                       O. Fe-Nd       0.0        0.0       0.0                                       P. Cu-Nd       0.0        0.0       0.0                                       Q. In-Nd       1.2        0.0       0.0                                       R. Zn-Nd       0.6        0.5       0.0                                       ______________________________________                                         .sup.(a) Conditions were: presulfiding with 50% H.sub.2 S in H.sub.2 at       350° C. for 30 min.; runs were made using 6 ml of catalyst; liquid     flow velocity of 3.3 V/V/hr.; a hydrogen flow rate of 75 ml/min.; atmos.      press.                                                                        .sup.(b) All catalysts except B utilized pre-sintered alumina made            according to method of Gass and Teichner referred to herein. Each of          catalysts M to R comprised 11.1 wt. % Nd and 2.35 wt. % of the specified      transition metal, calculated as the elemental metal based on the total        catalyst.                                                                     .sup.(c) Specific reactvity × 10.sup.-10.                          

What is claimed is:
 1. A process for the hydrodesulfurization of asulfur-containing hydrocarbon oil, which comprises: contacting said oilunder hydrodesulfurization conditions with hydrogen and a catalystconsisting essentially of a rare earth metal component selected from thegroup consisting of elemental rare earth metals, rare earth metal oxidesand rare earth metal sulfides wherein said rare earth metal of said rareearth metal component is selected from the group of elements havingatomic numbers ranging from 58 to 71, and (b) a non-rare earth metalcomponent selected from the group consisting of non-rare earth elementalmetals, non-rare earth metal oxides and non-rare earth metal sulfideswherein said non-rare earth metal is selected from the group consistingof Group IB, Group IIB and iron, cobalt or nickel of Group VIII of thePeriodic Table of Elements and an alumina support.
 2. The process ofclaim 1 wherein said rare earth metal component is present in an amountranging from about 1 to about 15 weight percent, calculated as theelemental metal based on the total catalyst, and wherein said non-rareearth metal component is present in an amount ranging from about 1 toabout 5 weight percent, calculated as the elemental metal based on thetotal catalyst.
 3. The process of claim 1 wherein said rare earth metalof said rare earth metal component is selected from the group ofelements having atomic numbers ranging from 59 to
 71. 4. The process ofclaim 1 wherein said rare earth metal is selected from the groupconsisting of Pr, Nd, Sm, Eu, Gd, DY, Er and Yb.
 5. The process of claim1 wherein said non-rare earth metal is selected from the groupconsisting of Co, Ni, Fe, Cu, and Zn.
 6. The process of claim 1 whereinsaid non-rare earth metal is selected from the group consisting of iron,cobalt and nickel.
 7. The process of claim 1 wherein said non-rare earthmetal component is cobalt.
 8. The process of claim 1 wherein said rareearth metal is present in an amount ranging from about 5 to about 15weight percent, calculated as the elemental metal, based on the totalcatalyst, and wherein said non-rare earth metal component is present inan amount ranging from about 1 to about 3 weight percent, calculated asthe elemental metal, based on the total catalyst.
 9. The process ofclaim 3 wherein said rare earth metal is selected from the groupconsisting of Pr; Nd; Sm; Eu; Gd; Dy; Er; and Yb.
 10. The process ofclaim 3 wherein said non-rare earth metal is selected from the groupconsisting of Co; Ni; Fe; Cu; and Zn.
 11. The process of claim 3 whereinsaid non-rare earth metal is cobalt.
 12. The process of claim 3 whereinsaid rare earth metal component is present in an amount ranging fromabout 5 to about 15 weight percent calculated as the metal based on thetotal catalyst and wherein said non-rare earth metal component ispresent in an amount ranging from about 1 to about 3 weight percentcalculated as the metal based on the total catalyst.
 13. The process ofclaim 3 wherein said non-rare earth metal component is selected from thegroup consisting of iron, cobalt and nickel.